Wednesday, March 25, 2009

IQ estimates by intended college major via SAT scores

++Addition++Lover of Wisdom recalls a table posted by Steve Sailer estimating IQ averages by completed major based on GRE scores. For the 22 fields of study included both as intended majors from the College Board's report and as completed majors in Steve's table, the estimated IQ values correlate with one another at .77 (p=0). So for the most part, the cognitive pecking order by degree stays the same ahead of entering school as it does once a BA has been obtained.

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Assuming the mean IQ of SAT test-takers included in a report by the College Board to be 103*, the estimated average IQ of students by intended college major follow. The estimates exclude writing results, which were added in 2005 and constitute what is generally considered the least objectively reliable part of the test**. The critical reading and mathematics (previously known as the quantitative section) portions are equally weighted:

Intended major

IQ

Interdisciplinary studies

114.0

Physical sciences

111.2

Mathematics and statistics

110.7

English and literature

110.1

Foreign language

109.8

Philosophy and religious studies

109.6

Social sciences

109.3

Library science

108.7

Engineering

108.5

Biological and biomedical sciences

107.7

Liberal arts & sciences and humanities

107.5

Area, ethnic, cultural, gender studies

106.8

Theology and religious vocations

106.4

Undecided

106.2

History

106.0

Natural resources and conservation

104.6

Military sciences

104.1

Computer and information sciences

103.9

Communication and journalism

103.5

Architecture

103.2

Visual and performing arts

103.0

Legal professions

102.8

Psychology

101.3

Business

101.2

Health professions

100.8

Engineering technicians

99.9

Education

99.3

Agriculture

99.2

Transportation

98.7

Other

97.8

Family and consumer sciences

97.5

Parks, recreation, leisure and fitness

97.5

Public administration and social services

96.6

Culinary services

96.5

Security and protection

95.9

Precision production

95.2

Construction trades

94.3

Mechanic and repair technician

93.3

Nothing too terribly surprising. Education is at the bottom of the degree fields not typically offered at vocational schools. The kids who want to study religion through a lens of mythology are a little smarter than the kids who want to be practitioners of it. All but the smartest kids tend to shy away from degrees requiring high level math courses, and while still in high school the sharpest of the sharp plan on double majoring. Those on the fence are not just unmotivated slackers. There is probably something to be said about putting one's feet into the university waters before deciding where you want to swim.

I went into business because I figured as a senior in high school I was already capable of doing almost everything required of me there. I was currently taking calculus and would be finished with it by the time I entered college. So statistics would be the only thing standing between me and graduation. I was able to muster up enough determination to tackle one uncertain course, but that was my max. And for the sake of my blogging avocation (heh, as well as my career, of course), in hindsight I'm glad I didn't pursue some other even safer major, like history or the humanities.

Those aspiring toward a legal career perform worse on the SAT than those hoping to go into other well-bred fields like science and engineering. Many of those on the lower end of the cognitive scale probably opt for other paths later on or are eventually screened out by the bar exam.

Intelligence and productivity proxy for one another, but the relationship certainly isn't perfect. Contrast the relatively strong performance of those pursuing a degree in ethnic, cultural, or gender studies, which will likely add no value to society if obtained, to the modest intelligence of those going into construction, craftsmanship, or mechnical repair, all degrees which will add real value, and you have demonstrated as much.

Using the same methodology, average IQ estimates by race among those who took the SAT in 2008:

* Using Wordsum scores from GSS data from 2000 to 2006, assuming a standard deviation of 15, the estimated mean IQ for whites with a bachelor's degree or higher (thus including those with MAs and PhDs) is 108.3 (for those who have attained exactly a bachelor's, I find a mean IQ of 105.9). The detailed report by the College Board for 2008 shows whites score a little more than one-fifth of one standard deviation higher than the SAT average for all test-takers. In terms of IQ, that translates to a 3 point advantage for whites relative to the entire SAT pool. If all of these test-takers were future college graduates, it would be reasonable to estimate the cohort's mean IQ at 105.3.

Of course, not all of them will earn a BA. Those who drop out will tend to be on the left half of the score distribution. The GSS shows relative to people with exactly 12 years of schooling (high school graduates), those with between one and three years of post-high school education (essentially those who have taken some college courses but have not graduated with a BA) are on average 37% of the way to the group with four to eight years of post-high school education. So if the average IQ of those who finished their educational careers with a high school diploma approximates the US' national average of 98, a reasonable estimate for the average IQ of SAT test-takers who will not go on to graduate with a BA is 100.7.

Roughly half of the test-takers will not earn a BA. Equally weighting the estimates for those who will attain at least a BA and those who will not yields an IQ score of 103. Consequently, I am working with the assumption that this is the average IQ score that corresponds to the average composite SAT score for those included in the College Board's report.

There are a lot of assumptions here. Further, there is no attempt to distinguish between the college-bound who take the SAT and those who do not, to estimate the BA completion rate by intended major, or to account for who switches majors during their college careers and why (ie, physics was too hard so I switched to education). But it's not worth getting caught up in plausible precision of this average IQ estimate. If it is felt that it should be two points higher (or lower), just add (or subtract) two points for the estimated average of each degree field. To the extent that the table above adds value, it is in the form of relative comparisons.

Tangentially, the GSS has two racial categories. The one that has been used for the life of the survey is broad--"white" is one of three choices, the remaining two being "black" and "other". I suspected estimates of white behavior would be skewed because of this, due to the inclusion of some Hispanics, Asians, and Native Americans. The more detailed GSS racial breakdown including 16 categories (introduced for use in the GSS in 2000), however, reveals that virtually everybody who chooses white in the three-category racial classification also chooses non-Hispanic white in the 16-category classification. The Wordsum scores for three-category whites and sixteen-category whites are virtually identical. During this decade, Hispanics, Asians, and Native Americans are apparently all choosing "other" in the three-category question, and there is little reason to think it was otherwise in the past.

** However, the scores by intended major including and excluding writing correlate virtually perfectly (r-squared=.99, p=0). Whether they are included or not does not change anything, suggesting that whatever reading and math are measuring (g to some extent), writing is tracking as well.

Thanks for pointing me to LoW's blog. I'll start looking at it regularly.

Peter,

Do many vocational schools require SAT scores? Some do, but I'm not aware of how unusual they are. I assume those studying agriculture are more likely to enroll in vocational schools than others who are pursuing degrees not offered by them (obviously). Don't know how large a percentage of students this effects, though.

Blode,

It would also be interesting to see scores for students upon graduation by major. Graduate testing offers some insight into this, but the majority that does not desire graduate education is being missed. Elite schools would hate this the most though, since it'd reveal their secrets of success--not making students smarter, but taking in smart students to begin with.

BGC,

From what I can tell, interdisciplinary studies in this context is synonymous with double majoring. So these are students who are doing architecture and engineering, humanities and history, etc.

In answer to BGC's questions:Holy frijoles, the subject is more complicated than you might think.

The reason I was surprised at that is, in my day, the interdisciplinary fields were in the building with a neon sign that flashed EASY on the top.

Thomas Sowell points out that a lot of them are in in fact non-disciplinary. "Easy" apparently doesn't mean "only dim students are attracted."

They included a lot of majors that could also be in the "Area, ethnic, cultural, gender studies" category. In fact, most interdisciplinary fields I can think of are represented on the list by one name or other, lending credence to Epigone's idea that the students in the interdisciplinary category are picking two or more major on their own and making a plan of study of their own design.

I just posted Steve Sailer's chart of IQ estimates by actual major to compare it to yours on potential major. It makes me wonder how "Interdisciplinary Studies" gets broken down into various majors, since it isn't mentioned on Steve's chart.

It just bugs me that people can simply categorize business into one category when there's such a wide disparity among accounting, finance, management and marketing. Also where's Political Science and International business/affairs? The latter will probably be tied with the interdisciplinary major.

Also does having multiple concentrations and minors count as an interdisciplinary major?